Poration osi new yokk



Nov. 13, 1928.

1,691,910 G. B. CROUSE ET AL VOLTAGE REGULATOR Original Filed Sept. 8, 1926 3 Sheets-Sheet l converfg Nov. 13, 1928. 1,691,910

G. B. cRousE ETAL VOLTAGE REGULATOR Original Filed Sept. 8, 1926 s Sheets-Sheet 2 Nov. 13, 1928.

1,691,910 G. B. CROUSE ET AL VOLTAGE REGULATOR Original Filed Sept. 8, 1926 3 Sheets-Sheet 3 gnmntou;

PORATION OF NEXV YORK.

VOLTAGE REGULATOR.

Original application filed September 8, 1926, SerialNo. 134,248. Divided and this application filed This invention relates to voltage regulators and more particularly to automatic regulators for controlling the voltage impressed upon a load line under variations in anelectrical condition which tends to alter the voltage across the load.

The invention is particularly useful in effecting a control of the output I oltage of an electrical converter. The control is usually designed to maintain theoutput voltage constant, but this is not may be such that the voltage across the load varies in the same sense or in, a sense opposite to that which would normally iaccompany a change in the critical electrical condition upon which the regulation is;based. In supplying current to'a load fronia sourcc'jol" energy and through an electrical converter, the particular electrical conditionwhich determines the regulation may be the input voltage, the voltage across the load itself, or the value of the load. p l

In accordance with th is invention, the de; sired regulation is effected by passing can rent from the source oiyfrom theload line through a regulatingresistance, and-controllin the effect of the resistance upon that current by simultaneously subjecting the resistance to the influencefof an additionalcurrent, which additional" current'zimayfpas's through the regulating ,resistanc e'or through a separate resistance thermally coupled thereto. The regulating resistanceniay be formed of material havinga. negligible or a high temperature-resistancecoeffi eient, and in the preferred embodiments oft-the invention the resistance istreefrommechanically movable parts and electric make-ancl-break contacts. Vhen the resistanceis formed of material having a. negligible temperature-resistance coefhcient. it is of the type commonly designated a fixed resistance. Sincethis termwould be misleading when applied to a resistance whose value varies with temperature changes, the term static resistance is employed in the following specification'and claims to desi nate a resistance ivhichis free from moving parts or make-and-hrealr contacts, butwhich may or may notbe formed September 15, 1926.

essential as the design ed. across the line,

vol g acros -th 't-o",i. 1 f '-t. d. in' thed of V and i ppa atu for I effecting vol'tagef r'egt la tji the load line c'irc'uitka .there l oii l' a 'r l t na Z i across apparatiisffo the load line paratus for effecting regulation Serial No. 135,691

of such material that its effective value varies with temperaturechanges.

This application is' a divisionof our copending application Serial Number 134,249, filed Sept. 8, 1926, which application includes a description of and generic claims to the present invention. The'claims of this application are restrictedito methods and apparatus which are'excluded by th e terms of the specific claims of 'our copenoling application.

An object of the 'inv'entionis to provide a method [of and apparati for effecting volt age regulation i' e'sis tanceisshuntgl hli an d 'th e effect, uponth I load line "v lta'ge' of lthe s un't resistance is determined regulatiii'gfcurrem which is t-hrougli the isllunt resistance, or thru'a' 'resifStan i s-thermally coupled there-to. A nothenobjec'tis'to provide a method ,4 of and apparatus for effecting a desired variationsin 'the load 'jresistan'c'e or in the load' A fur ther ob ect IS control the voltage aeross a; load line under "n h'yiincluding in teimj eraturewarant 'fl t mei and vntrb s hgm e eff Oft a resistance-upon 'tl elliic vot gej-by' passing which iir' en v esa-sfaf n ipi 'e h'l d' r th t loedaif Mqfes i ml y; ebie' s'je theihv n a area; pfmvfdeii ne te of and fi'eeting'vbfltfag'e regulation in luclest'g' resis of that lating'c urrent.

; 'These and otheriolijects 'of-the invention will be apparent ram the following specification when taken Withfjthe accompanying i i. l'is a circuitdiagfa n illustrating the invention asembodied 1n aln ot or-ojenerator;

Fig. 2 is a diagramofa gn ei al form ofapthe output side of a converter:' I

'Figs. 3, 4 and 5 are d agramsiotispecific I r ent- 'po tential bet withdrawniijo'rn the source of the secondary forms as applied to converters of the doublewave rectifier type; and

Figs. 6 and 7 are diagrams showing the invention as applied to motor-generators of the direct current-alternating current type. I,

The circuit diagram of Fig. 1 illustrates the invention as embodied in a rotary converter. The alternating current input terminals. 1- and 2 are shown as feeding power to a series type motor having a commutator 31 and a series field 32. This motor is joined by the shaft 33 to a direct current generator having a commutator 3% and a self-excited shunt field 35. The load 6 is joined tothe output of the motor by means of the wires 36 and 37. Inserted inthe shuntfield- 35 oftbe generator is the resistance bridgeltcomprising the four arms which' are seriallyconnected in a closedcircuitat'thejunction p'oints 11, 12,

1a and 14; g

v The 'c iu rrent' for controlling the effective vvalue oft-he resistance bridge R is aftr s r'me' having a'prirna'ry wifding 15, an iron core 16 and a seeondarywinding 17. One terminal. I I joinedio the junction point 12'of the br1dgej,'the otherterminalbeingconnectedto Juiicti Qnlpoirit mur o gh h i 18 .oeit firdn QQIdlQ- .1 i." The elerii'et'its pf the jsyste'rn should,

i itelei e t h ill fie ae t ew u de i r d] by; intrane nt 1w- Hater t the; iqaa ejwi-llibei'at. its "selected \.-a.lue'. v f .An. i q a'sedf inputp e al' tw e i th e mina s 1 and 2' i1 U k y1i fix f int-ease he a m n a, are therefore an increaseof l nat-ing'durrent e i at sfiii -ui tflwhis ia l de th wa i 'i e i'a' e .fm' erna g ur pt-.W 1 1 9. 3 5? a 'reasejofthe r s e in e pa's diiuth s it-ing fie d 3L nd t er ore .t l xi i mega .lacr s the terminals36 and '37' fifo'm 'tlii s'fcailsefi At the same time the increasefof inp"u,t potential has caused .an. increase,bf I' ced-of thefalt'ernating current motor; properly: proportioning the various element's of the circuit, and morefparticularlythe c oil 18 'and its core 19 n h r et t t qs. f. t e br dge. h

economy'of power and'permits greater flexib ility in design, itis not; essential to theoperation of the system. By increasing the proportion of alternating current ,fiowing through the bridge to that of; the direct current, regulation may besecured in the same manner as above. iVhile the invention has been described as controllingthe direct current output of the converter under varying alternating current input, it will be readily appreciated that suit able modification will permit a control of the alternating current output of a converter under conditions of varying direct current input. I I I I In the circuit of Fig. l, the regulation of the load line voltage is effected in accordance with changes of the input or source voltage. The regulation may, however, be eltected in accordance with variation in voltage across the load circuit or variations in the magnitude of the load. To secure a control of this type small variations in the voltage across the load are caused to effect relatively large variations of current in a regulating circuitwhich is connected across a static resistance in the load rc i I I i Inthecircuit of Fig.1), the numerals I and 2 indicate the terminalsofan alternat-ing'current source delivering energy to a converter 3 whi'ch suppli'es directcurrent; to the load 6. Theresistance R is includedi'n one'of the output lines of the converter and the current for ;regu lat-ing its effective value is withdrawn .fro: ithesource by .a transformer 15, 16, 17. 'flofc cntrol the magnitude of theregulating impress dac-ross the resistance bridge transtoriner' l f), 17, "from the voltage ps sthe'loadlinqan inductance 18', hav agon; 19, isprovided between one termina jb f the winding Hiandthe junction point 14' oftliejbridge The inductance 18 consists oj two coils whic'hare connected in parallel andfwounch'in-opposite directions, upon the outer legs'of a three-legged iron core. To control the react-ancc of thei nd'uetion 18, the magnetic saturation of the iron corc' 19 is contrplled by means of a coil 38 which is wound on the inner leg of the core and is coninccted in parallel with the load 6 through a series resistance 39 By properly proportion ing theiariolis elements of the rcgulating circuit a veryfsmall increase of voltage across the lo'ad 't} willjv be sufficient to eflect a. large ',i ncr'ea se of current flowing through the bridge fronrthecircuit-17. The change in magI}-itude of the regulating current produces a change of resistance between the pointsll and13of the bridge; The control is dependentupon a change in the voltage across the load and therefore only approximately constant voltage across the load can be secured, but the relative amount-of the variation may be reduced tozany desired degree by a. suitabledesign of thevpar'ts. I

Although not. limited in its application to a supply system for delivering a. substantially ripple-free current from an alternating current source the invention is particularly adapted for such use. A filter 4O ofany desired type may be included in the load line between the converter 3 and the load 6.. \Vhcr.

rent potential at the junction points 11 and 13 the passage-of the regulating current through the resistance bridge will not introduce an alternating current component into the output of the converter. The balance of the bridge is also effective to prevent a waste of direct current through the circuit of the secondary winding 17. The resistance 39 must permit the passage of suthcient'current to affect the desired regulation, but is preferably of such relatively high value that the amount of direct current required by the \-'oltage regulator will be small as compared tothe current passed over the load, The two sections of-the inductance 18 are so proportioned that no alternating current potential will be introduced-to .the load' circuit throughthccoil38. The circuit of'Fig.-3 illustrates an embodiment of the invention injwhich the regulating resistance may be formed ofmaterial which has a'negligible temperature-resistance coef-' ficient; Inthis circuit the numerals 1 and 2 indicate the terminals of an alternating current'supply line across which the transformer primary 41 is 'connectedi The transformer has a core 42:and 'apair of secondary wind ings 48,44,- for supplying! current to the rec tifi'ers '45; 46; respectively.1 Iuilre terminals 'of the: rect'ifiers 45; 46 areconnected to "each 'other' a'nd to bne side 47 o f'the-dimct'current 'loadlinei'the other rectifir terminals being connected to a; terminalof theirespective secondarywindi ng s-43 and 44 Elie-other terrninals of secondaries 43'-'44rar'e connected to each other throu'gh aseries resistance comprising-lsectidns 48,"49 whose junction:- point serves as the terminal: for the ot-her side 50sof the loadline'u- Thestatic resistance 48949 may be ofsubst-anti'ally constant value or its value may var'y with itster'npeiatiireii iThe minding for impressinga regulatin ivoltzigeyacrossthe static resistance;- is preferfiily formed in two sections ''51; 52 whose! ou'ter-rends are jbined tothose 1 terminals: o-{f t-he windings 43;; which are-connecteda the'static rresistance. The inner ends of ith'e sectioirs 51', 52 ref the regulatingsecondarv are connected through a; series inductance" comprising the'itvro opposite'ly wound coils 18'" on the outer legs-of the :three-legged' =c'ore 19". 2 Elm winding :38 for determining the magnetic-saturation of the core is preferably conn'ected tothe load line through az serie's resistance 39. A filter 40 may be used between the converter and the-load 6 to'remo've alternating current com pcnents from'the current's'upplyw WVhen the resistances 48- and 49 are of such material that-"they have a -high-temperatureresistance coefficient, theoperation is similar in a general way to'thatcf the circuit of Fig. 1. An increase of-input'alternati'ng current potential causes a large increase in alternating current circulating in the'circuit including the resistances'48'and 49. This causes an increase in temperature and therefore an increase in resistance of these units. As the static resistance is a series element of the direct current load circuit, an increase in its value causes a lesser portion of the increased direct current voltage to be passed to the load 6. The regulating effect is not due solely, however, to the change in resistance of the members 48, 49, but is modified by the fact that the voltage impressed upon the rectifiers is supplied in part by the intermediate windings 51; 52. The effective voltage as Well as the current supplied by the rcgulat ing winding therefore aticcts the voltage acrossthe load. The modifying action of the voltage drop may'best be understood by first analyzing the operation of the circuit as constructed with resistance elements 48 49 which are of substantially constant value.

' The effective alternating current voltage applied to a given rectifier, for instance, the rectifier 45, consists of two parts,.one applied from the winding'43 and the other arising from the voltage drop across the resistance 48 due't o the intermediate winding 51. The voltages-set up acrossthe terminals of the windings 43, 51' are dependent upon the source voltage and will both vary in the same sense; and at the'same rate with changes inthe source voltage. By a proper desi n of-the'elements the effect of a change in the voltage across the: winding-43- inay be com pensated, in wholc or input, by' the change in the voltage-drop across'the resistance48 which results from the simultaneouschange involtage inducedin the winding'51, as modified by the coil 18'. i The magnitude of the regulatingcurrent supplied by the winding 5.2 is determined by thc-reactance of the inductance-18 \vhiclr-is varicd in the'manner stated witlrreference to the circuit of When it is desired to make use of theactiou just described, the use of the inductance l8 is essential; as otherwise the dropacross the resistanoe would be a constant proportion of the source voltage. In the foregoing explanation the difference in 'phasebetween the 'voltage"of the-winding 43 and that impressed across the resistance 48 by-thc winding 51 nottaken' into account. This phase difference must be considered in thestri'zctural design of'a system, but docs notafi'ectthe validofthe above explanation of operation. Whilst-he above explanation has been directed to only one-half ofthejr ectifiersys tem,'it-Will be apparent that the-same effect takes place across the other half. The voltages of the coils 43, 44 willnot be in phase with the voltages established in the resistance 48, 49 by the regulating windings and this difference in phaseshould be taken into account in the design of a particular regulating system. The design of the parts will also be dependent upon the temperatiiren'esistaace Xllfi characteristics of the static resistance elements.

Returning to a consideration of the operation of the system when the elements 48 and 49 are formed of material having a high temperature-resistance (to-efficient, it will be apparent that the effective voltage drop to which current from the winding 42) is sub- ]ected on passage through the resistance .48 is dependent both upon the magnitude of the regulating current originating in the winding 51 and upon the voltage'drop to which that current is subjected on passing through the resistance. Both of these factors. must be considered in the structural design and their separate eifect-s maybe either aiding or opposing with respect to each other.

The embodiments illustrated. inFigs. 2 and 3 effect a regulation under varying conditions of load resistance-and.input'voltage, which regulation does-"not,-however maintain a constant voltage across the-load since it is this voltage which is the critical electrical condition upon which the controlis'based. The regulation-of the line voltage maybe made dependent upon the. .valueof the load resist ance by'including the loadfas one arm of a bridg ClIClllt;

1,: :11'.;i.-. Many oftlie elements of; a circuit-for .effecting regulation by fluctuations in the magnitude ofv the load maybe practically identical with the icorresponding elementsqof-a circuit in-which-the regulation isbased on variations of thevoltage across the load. The circuit of Fig.- 4 differs from-that of-Fig. 335 to: the connections between? the: cont-r01 Y wind.- ing 38 and the load-line. -"The-load.line and the control winding38. are. arranged as; the cross-armsof abridge whichisformetl by the load-6 and the impedanCBSI 5.3; 54 and 55; The resistance 55 should .be; oiicon'rparatively low value and of the same current carrying capacity asthe load- 6: F 'IlhG E QS- Stit CB and 54: should prefierably ibe ofihighmesistance in comparisonwith-.-the loadifiiandr-rejsistance .55, land may :be of? smaller, current carrying capacityn". 1 It will be noted that theeircuitsof Eigs; .3 and 4 differ as to :the;.relative:;$ense-ofithe windings 43, H and the.-windings\51, 520i the regulatingcircuit-As sl1o.\-'u.in..-Fig. 3, the sets of secondary windings are opposed and in Fig. 4 the secondariesare-zall wound in the same sense. The relative sensef of the windings must be considered in the design of the circuit elements, buteither-the opposed or aiding windings maybe used in a particular circuit." .When the load'line'sec-ondary 43 and the regulating 'secondaryafilare wound in the same sense, the bridge in .wl1ich-. the load 6 is included should be so arranged thata-decrease in the load rjesistancewill cause: an increase of direct current to flow in the control winding 38. This increase of current willchange the magnetic saturationot the core 19, a greater alternating current will therefore be allowed to pass from winding 51 to the resistance 48, a larger regulating potential drop across this element will be applied to aid the voltage of the secondary l3, and thus an increase in voltage across the load line 5L7, 50 will result. By a proper design of the vari: ous elements the voltage across the load may be kept constant as the line voltage changes in accordance with fluctuations in the load resistance. This system of regulation does not correct for variation in the source voltage. If the voltageof the source is subject to objectionable large variations, an additional control of the types shown iii-Figs. .1 and 2 of our copending application may be combined with the controljcircuit otFig. 4.

As shown in Fig. 5, one'e-lement of a filter in the direct current line may 'serveas .the static resistance. The terminals-.1,-2;of; an alternating current. source. energizei'tl ez pri'-. mary winding-56 of a transformer having a double'secondary winding. 57 for passing bot-h halves of the current wave to the rectifiers- 58, 59. The direct current load-line. (30, 61 is connected-to the-junction ofthe rectijfiers-and-to the central tap of thesecondary '57 i'n-theusual manner. The filter for eliminatingialternating current components from r t-he current pas'sed-to the .load'fi 'takesit-he form oia well-.kn'own type having series induetances 62; 63 'anda resistance connected across the line between their junction :point and zthereturn 'iwire 611- This -cross resistance is given the form of the resistance bridge R suclrasdescribed above. The four .elements-are .fo'rmed :of materialhaving; a high temperature-resistance characteristi'ciand are serially connected: in a closed: circuit atth'e juiictionpbints11512; 13 and 14;," The: uric.- tionpoints 11 iii-Dd; 13 are connected to. opposite sidesoftherdirebt-current line andthe regulating current is introduced through the other pair .12, 14- of conjugate junction points. a Across the: alternatin current supplyline are "connected the parallel primary: windings 641and 65 .wound on the 'outsideglegs'of -a three-legged ironcOre-GG. wThese 'win'dings are so connected-that the flux generated by the'rcu rrent flowing into. thein traverses only the outside legs: and: does not 5 flow through the center 'lg- -In series with the primaries 64:and 65 i's connected the coil 67 on its iron core 68. This-coiland'tcore is so design'ed that the iron will not be. saturatedin !tl1e n0 r mal working range of the system. The secondaries of the transformerwhose core is 66 are-69-and 7 0. ThBSB SWODQaIlGS are shown as;connected -'n. series and-their output. is join'edto the'zjunction points 12 and l t-of the resistance bridge. Thebridge is so designed that it will-be. balanced for. alternatingcurrents at ;.the points 11 and 1-3 and thereforefino alternating current will be apof the resistance between plied to the filter, system by the secondaries 69 and 70. Similarly the bridge is balanced for direct current between the points 12'and 14 and therefore no direct current will escape from the filter system and be wasted in the secondaries.

On the center leg olthe core 66 is placed a winding 71 connected across the direct current load 6 and having in series with it a limiting resistance 72.

It will be apparent that if the resistance between the points 11 and 13 can be automatically increased as the voltage acrosslthe load 6 tends to fall, that by proper proportion these points in relation tothe resistance of the inducta-nces G2 and 63,-='approxiniate compensation of the load -voltage may be secured under condiage.- --T-he-resistance, between the junction pointsill and 13 is: principally determined by the alternating current'voltage-applied .be-v tween the! points 12 andyl h-i .This :voltage ,isdetermined by the ;line;.voltage. and: by the relative distribution of this voltagebetween the 001167 e and the parallel :priniaries .Ghand 65.. Since: the core; 68 ;is

amount! of; coil 71.

direct current flowing:= 'AS. the, voltage: across fthcr 10mm increases in. the:

more current flows :inf the c'oil 71, causing the reactance, of the; primaries {Ms-and -65 to be reduced, thus causing a reduction-of'alternah'.

ing current voltage applied between; Eth'e of the coil 62:.and -thus/preventing' further: increaseot voltage across theiloadvfisi Regu-z lation vis approximate 'asgtheicriticahelectrical a .which it is based: is [the wioltcondition upon age across the load, ibu'tuanyi desi red degree of approximation may be securedmiz i' r i In each? of the above convertercircuitsfthe magnitude or the output vltage h'as' been de terniined by a regulating current-withdrawn from the source-or'iinput sideof theconverter and .controlledby fluctuations Eat the input and/ori output :sidew; The invention is also:

useful in-connection with frequency control of motor-generatorsof the direct current al- I I, v jj 1 if; i-l'elements ofthese circuits.

In the-.circuit diagram f. Fig; 6, the n11- mera ls 73, :74 indicate the direct. current line or 1 source of 1 energy across which'zthe motor- 5 ternating-type. w

is connected. The-motor armatur '75 rotates in the field established by: the shunt Winding 76 and the v differential; winding 5 7 7 '-WhiCl1 latter winding is supplied-from through, the temperature-variant resistance tions of, -"arying load resistance or line volt- I controlled in never. saturated the I field strength react-ance of the coil 67 {will remain substan-iv tially; constant, (whereas; the reaetance of 'the primaries (Stand, will: rvary-mvith -:the.-

v=. act the I tendency yond thetransformer primary 82.

the source bridge R. The field 78 of the generator armature 79 is driven from motor armature 76 by a shaft 80 or the like. The regulating circuit for controlling the effective value of the static resistance includes the inductance 18 on a closed iron core 19 and the secondary 81 of an iron core transformer, the primary 82 of the transformer being connected across the alternating current output or load line. The regulating circuit and the difi'erential winding are connected across the conjugate pairs of junction points, 12, let and l1, 13, respectively.

A change in the source voltage will cause a change in the current flowing in the generator Held 78, which change will be reflected in the voltage of the alternating current output and also in the output of the secondary winding 81 of the regulating transformer. This change in regulating current will result in a sequently in the current flowing in the dilfer- :ential field winding 77. As a general rule, the

current flowing in the dilferentiat winding is such manner that the total motor age i applied lt,1 ior example,

so varies, in relation to the volt to the motor armature,;that.av constant'motor speed and consequently a con-i ,sta'nt-ioutput frequency. will= be maintained; thesvoltage across-the source lines 73, 7t rises, the motor .would ordinarily Dir increase 111 SPeed The increase in source volt- I .sistance. The resistance of the bridge'R is the current flowing in the.

thus increased and differential winding 77 is thereby reduced. "The motor :iield strength; is therefore in the elements, the strength. may be just sutficient to counterwhic'hresultedfroni the increase of source voltage.*-

The motor-generator circuit of Fig. 7 shows. 1 this frequency control system combined with .an output Voltage control; --control elements maypbe identical with the -various elements of Fig. 6 and the same'numerals are therefore applied'to corresponding. i The control of the:

The frequency alternating current voltage impressed 'upon age results in -afistronger generator field and consequently anfincreased alternating current voltage. The increased output voltage opercreased and. consequently:theimotor-speed tends-to. fall.- -Byan 1 appropriate designof increase in motorufield toward increased speed the load-lineis effected by a second tempera-r T ture-variantresistance bridge Rwhich is.in-

eluded in the load lineof the alternator be- The load line is connected to the bridge at conjugate junction pointsll and 13', and the regulat ing current is supplied by connecting the ill source across the other pair of junction points 12' and 14. If the source voltage increases, the frequency regulation is effected in the manner described above, and the increased source voltage causes more direct current to pass through bridge R to thereby increase the resistance offered to the alternating current. By appropriate design, the entire iiicrease in alternating current output voltage may be absorbed in the bridgeR', consequently arsubstantially constant output voltage will be maintained under conditions of varying supply voltage. Attention is directed to the fact that an automatic regulation of voltage as to magnitude and/or as to frequency maybe obtained without the useof: mechanically movable parts or electric make-and-brealr devices. It

willbe obvious-that .whilo certain' elenients may be moved for. effecting a preliminary orocc asional adjustment ofa; particular system, the: actual regulation for variations in a critical. electrical condition will take' place automatically when ,the parts are suitably dc signed to efiect that result v It is to be undeitstood however,- that while the. invention may be embodied in' arr automatica.regulatorpmanually operated switches orother-' devices --may-- be used 'inconnection withzor. as substitutes for=thej elements-which cegiilation .-.=So far as a pefiectthe automatic 7 V itisbroadlyneav to effect plicants are aware,

voltage regulation r-byi introducing: a resist-- mice as an element -o1':the;circuitin-w-hicli reg ulationv is des'ired and controllnrgqthe eflect' ofthatresistance on the voltage oat-the circuit by simultaneously subjecting xthealresistance :1

to the i-nfl hence .of a;- regulatingrcurient which is varied: in saccdrdance with" the desired aria-7 ture of the re ulation, -so:;that regulation =-1S- dire'ctly effected by ithe potentialacross the resistance.- Wheni the resistance :is of theztenii pera'turewaria'nt type the regulatingcurrent may be passedfthrough thegregulating. resistance orthrough a separate: resistanethermaF ly coupled thereto," I

The :several circuits descr bed herein 1nd cate. the manner in which the-inventionni'ay be pi'acticed, -but' it isapparentithat-the invention is not cuits.

1; Avoltage regulatorfor an electrical sys-z tem :of the type including a having a resistance as one cliaracterizedby the circuit. is provided across: said resistance to determinetheetfective voltage drop to which.

limited to these illustrativecirlelement thereof,

line current is subjected on passagethrough.

said resistance. -.r e

E2.- A voltage regulator as set-forth .in claim 1 wherein saidresistance comprises a static resistance; i. t 7 3; -A voltage regulator as set forth in claim 1 wherein said,resistance'comprises-astatics:

line and a filter resistance having ailiigh teinpcrature-i'esistance coefficient.

4. In a voltage regulator for electrical systems comprising a source of energy, a load line, and circuit elements for energizing said load line from said source, the combination of a static resistance included in said circuit elements, a circuit additional to said circuit elements for delivering a current to said resistance to directly effect regulation by the potential across said resistance, and means for controlling the magnitude of said regulating current in accordance with variations in the voltage across the load.

5. The invention as set forth in claim 4, wherein said additional circuit is connected to said source to withdraw energy therefrom. I V 6. In an electrical system, the combination a with a source of energy, a converter, load -line,: and circuit connections for-energizing saidload line by means of said converter, of 1 a static resistance included in said ciicuit con- --nections and traversed by current delivered from said converter, and means additional to said circuitconnections and controlled by the voltage-of said load liiie for passing a current through said resistance to directly efiect regulation by the potential across said resistance, whereby the voltage 'drop to which said conveit er-delivered current is subjected on passage through said resistance is varied as a .function of the load line voltage.

7. Ihe :in'vntion as set fOl'th in claim 6 .wherein said means includes a coupling to the 1 said source to withdraw the regulating cur rent therefrom.

.a converter, a load lil le energized from ance having a high temperature resistarice co- :eificient and-arrangedin the circuit of said converter, means for heating said resistance iwith current withdrawnfrom said source to" 9..An .electrical converter for use between I a source of electrical energy and" a load line,

said converter comprising circuit elements for connectionacross-a source ofienergy, circuit means cooperating with said elements and nientsand means: that it may-be traversed by both source and line current, and means for controlling the magnitude of said source cur- 'which said line current is subjected onpassage through said icsistance varies with chi 'nges '3 in the-line voltage to directly effect regulation by- -the potential across the resistance.

10;:The invention as set fort-h in claim 9,

.111 an electrical system, a source ofen'j' "i i :fisaid source-by: said converter, a static resist adapted.to-.-deliver.current to a load line, a 2'; .sta'ticresistance so associated with said eleifaetrthat a regulating renti'iir-accordance with variations in line I voltage,iwhereby the effective-voltage drop to wherein said resistance comprises four see tions of high itemperature-resistancei coetficient and serially connected.to.-form the four side arms of a \Vheatstone bridge, the said; circuit'element'szand circuitfmeanabeing connected as the respective cross arms ofsaid bridge.

11: Inan electrical system for supplying filterecU-ciwrent to aJoadQwload line for connection across a sourceof current, a filter having impedance in series with the load and a static resistance in shunt thereto, and a regulating circuit connected across said resistance to control the effective voltage drop to which load line current is subjected on passage through said impedance.

12. In an electrical system for supplying filtered direct current to a load, a load line for connection across a source of current, a filter having impedance in series with the load and resistance in shunt thereto, said resistance having a high temperature-resistance coefficient, and a regulating circuit for heating said resistance to determine the effective value thereof.

13. The invention as set forth in claim 12, wherein said resistance comprises four sections arranged as the side arms of a VVheatstone bridge, the load line and-the regulating circuit being connected to the respective conjugate pairs of junction points of said bridge.

14. Apparatus for supplying direct current at substantially constant voltage to a load from an alternating current source, comprising a rectifier for connection between said load and said source, a filter at the output side of said rectifier, a static resistance traversed by rectifiercurrent, means for simultaneously passing a regulating current through said resistance, and means for varying the magnitude of said regulating current in accordance with variations in the voltage across the load.

15. A voltage regulator for an electrical system of the type including a line and a filter having a resistance as one element thereof, characterized by the fact that a regulating circuit is provided across said resistance to determine the effective voltage drop to which line current is subjected on passage throu h said resistance, and means are provided in t e regulating circuit for causing small variations in the voltage to be regulated to cause relatively large variations of regulating current in the resistance.

16. A voltage regulator for an electrical system of the type including a line and a filter having a resistance as one element thereof, characterized by the fact that a regulating circuit is provided across said resistance to determine the effective voltage drop to which line current is subjected on passage through said resistance, and a coil is provided in the regulating circuit wound upon an iron core the circuit connections between the conver substantially at the point of saturation at the lowest opera ting voltage of the source.

'17. In a voltage-regulator for electrical systems comprising a source of current, a load and circuit connections between the source and the load, the combination of a static resistance in the connections, an additional circuit forrdelivering a regulating current to the resistance,.means for controlling the regulating current in accordance with variations in voltage across the load and means in the addi tional circuit for causing small variations in the voltage across the load to cause relatively large variations of regulating current.

18. In a voltage regulator for electrical systems comprising a source of current, a load and circuit connections between the source and the load, the combinations of a static re sistance in the connections, an additional circuit for delivering a regulating current to the resistance, means for controlling the regulating current in accordance with variations in Voltage across the load and a coil in the additional circuit wound upon an iron core substantially at the point of saturation at the lowest operating voltage of the source.

19. A voltage regulator for an electrical system of the type including a converter connected between a source of energy and a load line, the combination of a static resistance in the. circuit connections between the converter and the load, an additional circuit for delivering a regulating current to the resistance, means for controlling the regulating current voltage across the load to cause relatively large variations of regulating current.

20. A voltage regulator for an electrical system of the type including a converter connected between a source of energy and a load line, the combination of a static resistance in ter and the load, an additional circuit for delivering a regulating current to the resistance, means for controlling the regulating current in accordance with variations in voltage across the load and a coil in the additional circuit wound upon an iron core substantially at the point of saturation at the lowest operating voltage of the source.

21. In an electrical system for supplying filtered current to a load, a load line for connection across a source of current, a filter having impedance in series with the load and a static resistance in shunt thereto, circuit connected across said resistance to control the eifective load line current is through said impedance, and means in the regulating circuit for tions in the voltage to be regulated to cause relatively large variations of regulation current in the resistance.

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nectiondcros' a source of currehqa filter liiwing impedance in series: with? the load and a static resistance iii-Shunt thereto, it regulatmg circuit connected across said rsistance to control the eflcctive-voltzige drop to which said: line current is subjected: on through said impdancqmnfl-arcoil in the re ulating circuit wound upon an iron core suhstantially at the point of saturation at the lowest operating voltage of the source of cur rent.

In testimony whereof, we afilx our sigma t'ures.

GEORGE B. cnousi z. JACOB L. JATLOW. 4 

